Particle therapy system and method

• US 7,439,528 B2
• Filed: 11/05/2004
• Issued: 10/21/2008
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nishiuchi, Hideaki, Matsuda, Koji, Umezawa, Masumi, Ike, Katsuhisa
• Primary Examiner(s): Berman; Jack I
• Assistant Examiner(s): SMYTH, ANDREW P
• Application Number:
  US10/981,505
• Publication Number:
  US 20050099145A1
• Time in Patent Office: 1,446 Days
• Field of Search: 2504921-4923
• US Class Current: 250/492.3
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 2007/008 for measuring beam parameters
• CPC Class Codes: H05H 7/06 Two-beam arrangements; Multi-beam arrangements storage rings; Electron rings

Abstract

A particle therapy system capable of confirming energy of an accelerated charged particle beam before the charged particle beam is irradiated to an irradiation target. A beam position monitor is disposed in a synchrotron, and a cavity voltage monitor is associated with an RF cavity for acceleration. An ion beam orbiting within the synchrotron is accelerated with application of an RF voltage applied to the RF cavity and is extracted from the synchrotron with application of an RF voltage applied to an RF knockout electrode. Based on a cavity voltage signal detected by the cavity voltage monitor, a frequency counter measures the frequency of the RF voltage applied to the RF cavity. Based on a voltage detected by the beam position monitor, a beam signal processing unit measures the position of a beam orbit. Based on the frequency of the RF voltage and the position of the beam orbit, the energy judgment processing unit determines whether energy of the ion beam after the end of the acceleration is normal or abnormal.

Claims

1. A particle therapy system comprising:

a circular accelerator for accelerating a charged particle beam, said circular accelerator including a cavity for applying a radio frequency wave to accelerate the charged particle beam;

a charged particle beam irradiation apparatus for irradiating the charged particle beam extracted from said circular accelerator to an irradiation target;

a frequency counter for measuring the frequency of said radio frequency wave applied by said cavity to accelerate the charged particle beam or the revolution frequency of the charged particle beam orbiting within said circular accelerator;

a radial beam position measuring device for measuring the orbit position of the charged particle beam orbiting within said circular accelerator; and

an energy determination device for determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator, and wherein said energy determination device determines the energy of the charged particle beam orbiting within said circular accelerator based on the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration, and the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration.

4. A particle therapy system according to claim 1, wherein

said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is normal, when the frequency of said radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator measured by said frequency counter after the end of the acceleration is within a first allowable range and the orbit position of the charged particle beam orbiting within said circular accelerator measured by said radial beam position measuring device after the end of the acceleration is within a second allowable range.

5. A particle therapy system according to claim 1, wherein

said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is abnormal, when the frequency of said radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator measured by said frequency counter after the end of the acceleration is outside a first allowable range or the orbit position of the charged particle beam orbiting within said circular accelerator measured by said radial beam position measuring device after the end of the acceleration is outside a second allowable range.

8. A particle therapy system according to any one of claims 1 to 3, further comprising a beam intensity determination device for determining beam intensity of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator.

9. A particle therapy system according to claim 8, wherein said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is normal, when the beam intensity is within a third allowable range.

10. A particle therapy system according to claim 8, wherein said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is abnormal, when the beam intensity is outside a third allowable range.

11. A particle therapy system according to any one of claims 1 to 3, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator is normal, and for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is abnormal.

12. A particle therapy system according to claim 8, further comprising a second safety device for permitting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting within said circular accelerator is normal, and for inhibiting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the orbiting charged particle beam is abnormal.

13. A particle therapy system according to claim 4, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator is normal.

14. A particle therapy system according to claim 5, further comprising a first safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator is abnormal.

15. A particle therapy system according to claim 9, further comprising a second safety device for permitting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting within said circular accelerator is normal.

16. A particle therapy system according to claim 10, further comprising a second safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting within said circular accelerator is abnormal.

26. A particle therapy system according to claim 1, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the frequency of the radio frequency wave applied for accelerating the charged particle beam by the accelerating cavity provided to said circular accelerator, or the revolution frequency of the charged particle beam orbiting within said circular accelerator, and the orbit position of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the frequency of the radio frequency wave or the revolution frequency of the charged particle beam and the orbit position of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, and determines whether the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration is within a first allowable range determined based on the frequency of the radio frequency wave or the revolution frequency of the charged particle beam obtained from said table data, and whether the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration is within a second allowable range determined based on the orbit position of the charged particle beam obtained from said table data.

27. A particle therapy system according to claim 1, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the frequency of the radio frequency wave applied for accelerating the charged particle beam by the accelerating cavity provided to said circular accelerator, or the revolution frequency of the charged particle beam orbiting within said circular accelerator, and the orbit position of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the frequency of the radio frequency wave or the revolution frequency of the charged particle beam and the orbit position of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, calculates a frequency deviation between the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam obtained from said table data and calculates an orbit position deviation between the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration and the orbit position of the charged particle beam obtained from said table data, and determines whether said frequency deviation and said orbit position deviation are within respective allowable ranges.

2. A particle therapy system comprising:

a circular accelerator for accelerating a charged particle beam, said circular accelerator including a bending magnet;

a charged particle beam irradiation apparatus for irradiating the charged particle beam extracted from said circular accelerator to an irradiation target;

a bending magnetic field strength measuring device for measuring the strength of the bending magnetic field of said bending magnet;

a radial beam position measuring device for measuring the orbit position of the charged particle beam orbiting within said circular accelerator; and

an energy determination device for determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator, and wherein said energy determination device determines the energy of the charged particle beam orbiting within said circular accelerator based on the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration and the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration.

6. A particle therapy system according to claim 2, wherein

said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is normal, when the strength of the bending magnetic field of said bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is within a first allowable range and an orbit position of the charged particle beam orbiting within said circular accelerator measured by said radial beam position measuring device after the end of the acceleration is within a second allowable range.

7. A particle therapy system according to claim 2, wherein

said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator after the end of the acceleration is abnormal, when the strength of the bending magnetic field of said bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is outside a first allowable range or the orbit position of the charged particle beam orbiting within said circular accelerator measured by said radial beam position measuring device after the end of the acceleration is outside a second allowable range.

17. A particle therapy system according to claim 6, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator is normal.

18. A particle therapy system according to claim 7, further comprising a first safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the charged particle beam orbiting within said circular accelerator is abnormal.

28. A particle therapy system according to claim 2, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the strength of the bending magnetic field of the bending magnet provided to said circular accelerator and the orbit position of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the strength of the bending magnetic field of the bending magnet and the orbit position of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, and determines whether the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is within a first allowable range determined based on the strength of the bending magnetic field of the bending magnet obtained from said table data, and whether the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration is within a second allowable range determined based on the orbit position of the charged particle beam obtained from said table data.

29. A particle therapy system according to claim 2, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the strength of the bending magnetic field of the bending magnet provided to said circular accelerator and the orbit position of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the strength of the bending magnetic field of the bending magnet and the orbit position of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, calculates a magnetic field strength deviation between the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration and the strength of the bending magnetic field of the bending magnet obtained from said table data and calculates an orbit position deviation between the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration and the orbit position of the charged particle beam obtained from said table data, and determines whether said magnetic field strength deviation and said orbit position deviation are within respective allowable ranges.

3. A particle therapy system comprising:

a circular accelerator for accelerating a charged particle beam, said circular accelerator including a cavity for applying a radio frequency wave to accelerate the charged particle beam, and a bending magnet;

a charged particle beam irradiation apparatus for irradiating the charged particle beam extracted from said circular accelerator to an irradiation target;

a bending magnetic field strength measuring device for measuring the strength of the bending magnetic field of said bending magnet;

a frequency counter for measuring the frequency of said radio frequency wave applied by said cavity to accelerate the charged particle beam or the revolution frequency of the charged particle beam orbiting within said circular accelerator; and

an energy determination device for determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator, and wherein said energy determination device determines the energy of the charged particle beam orbiting within said circular accelerator based on the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration.

19. A particle therapy system according to claim 3, wherein

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is normal, when the strength of the bending magnetic field of said bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is within a first allowable range and the frequency of said radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator measured by said frequency counter after the end of the acceleration is within a second allowable range.

20. A particle therapy system according to claim 3, wherein

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is abnormal, when the strength of a bending magnetic field of said bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is outside a first allowable range, or the frequency of said radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator measured by said frequency counter after the end of the acceleration is outside a second allowable range.

30. A particle therapy system according to claim 3, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the strength of the bending magnetic field of the bending magnet provided to said circular accelerator and the frequency of the radio frequency wave applied for accelerating the charged particle beam by the accelerating cavity provided to said circular accelerator, or the revolution frequency of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the strength of the bending magnetic field of the bending magnet and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, and determines whether the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration is within a first allowable range determined based on the strength of the bending magnetic field of the bending magnet obtained from said table data, and whether the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration is within a second allowable range determined based on the frequency of the radio frequency wave or the revolution frequency of the charged particle beam obtained from said table data.

31. A particle therapy system according to claim 3, further comprising table data in which the energy of the charged particle beam determined beforehand by measurement is correlated with the strength of the bending magnetic field of the bending magnet provided to said circular accelerator and the frequency of the radio frequency wave applied for accelerating the charged particle beam by the accelerating cavity provided to said circular accelerator, or the revolution frequency of the charged particle beam orbiting within said circular accelerator, and

wherein said energy determination device obtains from said table data the strength of the bending magnetic field of the bending magnet and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam corresponding to a predetermined value of the energy of the charged particle beam, calculates a magnetic field strength deviation between the strength of the bending magnetic field of the bending magnet measured by said bending magnetic field strength measuring device after the end of the acceleration and the strength of the bending magnetic field of the bending magnet obtained from said table data and calculates a frequency deviation between the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam obtained from said table data, and determines whether said magnetic field strength deviation and said frequency are within respective allowable ranges.

21. A method of extracting a charged particle beam comprising the steps of:

accelerating a charged particle beam within a circular accelerator;

determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator; and

extracting said charged particle beam from said circular accelerator after completion of said energy determination, and wherein said energy determination is carried out based on a frequency of a radio frequency wave applied for accelerating the charged particle beam by an accelerating cavity provided to said circular accelerator, or a revolution frequency of the charged particle beam orbiting within said circular accelerator, and an orbit position of the charged particle beam orbiting within said circular accelerator, the frequency of the radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator and the orbit position of the charged particle beam orbiting within said circular accelerator used for the energy determination being the value measured after the end of the acceleration.

24. A method of extracting a charged particle beam according to any one of claims 21 to 23 further comprising the step of permitting extraction of the charged particle beam from said circular accelerator when in said energy determination, it is determined that the energy of the orbiting charged particle beam is normal.

25. A method of extracting a charged particle beam according to any one of claims 21 to 23, further comprising the step of permitting extraction of the charged particle beam from said circular accelerator when in said energy determination, it is determined that a beam intensity of the orbiting charged particle beam is normal.

22. A method of extracting a charged particle beam comprising the steps of:

accelerating a charged particle beam within a circular accelerator;

determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator; and

extracting said charged particle beam from said circular accelerator after completion of said energy determination, and wherein said energy determination is carried out based on a strength of a bending magnetic field of a bending magnet provided to said circular accelerator and an orbit position of the charged particle beam orbiting within said circular accelerator, the strength of the bending magnetic field of the bending magnet and the orbit position of the charged particle beam orbiting within said circular acceleratator used for the energy determination being the values measured after the end of the acceleration.

23. A method of extracting a charged particle beam comprising the steps of:

accelerating a charged particle beam within a circular accelerator;

determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator and before extraction of the charged particle beam from said circular accelerator; and

extracting said charged particle beam from said circular accelerator after completion of said energy determination, and wherein said energy determination is carried out based on a strength of a bending magnetic field of a bending magnet provided to said circular accelerator and a frequency of a radio frequency wave applied for accelerating the charged particle beam by an accelerating cavity provided to said circular accelerator, or a revolution frequency of the charged particle beam orbiting within said circular accelerator, the strength of the bending magnetic field of the bending magnet and the frequency of the radio frequency wave or the revolution frequency of the charged particle beam orbiting within said circular accelerator used for the energy determination being the values measured after the end of the acceleration.